Obafemi Martins has drawn interest from a host of Premiership clubs after he put in a transfer request yesterday following Hernán Crespo's two-year loan to Internazionale from Chelsea.

The champions may be among those who would entertain a move for the Nigerian after acceding to Crespo's request to return to Italy, though the strongest overtures will come from Portsmouth. The Fratton Park club are desperate for a proven striker having been thwarted in their efforts to sign Nicolas Anelka.

With Lomana Lualua unsettled on the South Coast Martins, whose pace, vision and direct running shredded Arsenal's defence when Inter won a Champions League group match at Highbury 3-0 three years ago, would be a superb acquisition for Pompey. However, it would require all of Harry Redknapp's charisma to persuade a player of Martins' calibre to swap the San Siro for a dilapidated stadium and training facilities.

Newcastle, whose manager Glenn Roeder saw Martins score in Inter's 3-2 win over Porto in Amsterdam on Saturday - would not have those difficulties in trying to sell the club to Martins and may be able to offer Uefa Cup football via the Intertoto Cup . That may make Tottenham, definite Uefa Cup qualifiers, a more attractive destination for the Nigerian. But the White Hart Lane club have yet to show any firm interest and will continue to monitor the situation.

Martins' transfer request was directly linked to Crespo's return to Inter, which was completed yesterday. "I have to thank Chelsea, the chairman and the coach because they understood what I wanted as a man and they have made me happy," said the Argentina striker. "It was hard when I [first] left to join Chelsea, I still remember I cried when leaving Appiano Gentile. What I felt was like leaving a big family and thinking I would not have another chance. But I have it now and I'm keeping hold of it.

"It is true that I have a special, sentimental and now legal relationship with Italy. I am officially an Italian citizen. I have an Italian wife and two Milanese daughters, Nicole and Sofia. They are at home here."

Posters highlighting target areas for referees are to be plastered on every dressing-room wall in the country before the start of the new season. The Premier League is leading what it calls "a self-policing" move in a campaign to clean up the game at all levels, backed by the League Managers Association and the PFA.

Referees are to take a firmer line on four key offences - cheating, dissent, elbowing and mass confrontation of officials. "It's clear that everyone, including managers and players, don't want to see some of the less edifying elements in the game," commented a Premier League spokesman. We want to encourage an element of self-policing. It's an attempt to manage these issues through communication rather than cracking down."

Sir Bobby Robson was released from hospital yesterday but will undergo further tests this week. The former England manager was taken to hospital during Ipswich's game with Crystal Palace on Saturday after complaining of feeling unwell 10 minutes into the match.

"I'm happy to report he left this morning . . . unaided, with no medical support, and he is travelling with his wife Elsie back to his home in Newcastle," said Hugh Davis, the 73-year-old's former consultant and close friend. "He is in good spirits and back to his normal self. There will be further tests in Newcastle."

Before the match Robson had been on the Portman Road pitch waving to the crowd in his new capacity as president of the club he managed for 13 years.